In recent years, demand for high-rise buildings with a plurality of elevators has been increasing. In such high-rise buildings, when building sways or shakings occur due to strong winds and earthquakes, long members such as control cables and tension members of elevator systems tend to swing and collide against elevator equipments or caught by support members located within a hoistway, which can cause damage to the elevator equipments, control cables and tension members.
As a prior art detection device which performs elevator control by detecting the swinging or sway of a building caused by earthquakes or strong winds, Japanese Patent Publication No. 2007-153520 A discloses a building sway detector operation device including two pendulum sensors. These pendulum sensors are used for detecting the swing of the pendulums corresponding to shaking degree of the building. If pendulums arranged within respective cylinders of the pendulum sensors swing and collide against the inner periphery of the cylinders, the sensors transmit detection signals. The pendulum sensor cylinder of larger inner diameter detects the larger amplitude of a long-period earthquake.
However, such building sway detection operation apparatus is large and expensive. Typically, the average pendulum wire length is about 2 to 3 meters depending on the size of buildings, and thus a large space is required for the installation location. Furthermore, since the installation locations and installation conditions are different depending on the buildings, it is necessary to calibrate the length of the wire of the pendulums in each building.
Japanese Patent No. 5,205,969 discloses an elevator control system equipped with a seismic sensor comprising a two-dimensional accelerometer installed in the machine room of a building. However, such seismic sensor comprising a two-dimensional accelerometer is not able to detect long-period earthquakes in the same way as the pendulum sensors of Japanese Patent Publication No. 2007-153520 A. In this case, alternative detection means is required for detection of long-period earthquakes. Moreover, such an elevator control system is extremely difficult to retrofit to pre-existing elevator systems because of its complex mechanisms.
Meanwhile, there are a variety of well-known vibration control devices for damping vibrations or amplitudes of the building sway which is caused by strong winds or earthquakes including long-period earthquakes. Japanese Patent Publication No. 2010-255791 A discloses a conventional, active-type vibration control device which is installed in the upper portion of a high-rise building, so as to reduce the vibration or sway of the building during high winds or earthquakes. This type of active vibration control device is configured such that when the vibration control device detects the sway of the building due to earthquakes or strong winds, the movable mass on the vibration control device is driven by actuators to reciprocate with a phase lag of 90 degrees with respect to the amplitude of the building sway in such a way to reduce the amplitude of the sway of the building.
However, such devices are specialized in the damping of buildings, it is not possible to control the operation of elevators arranged in a high-rise building.